Re: [Caml-list] Multiboot problem

[David LONY <david.lony@pragmadev.com>]

Hi all,

I continue my multiboot sector but I'm blocked...To do so, I have 
implemented a dummy libC like the Funk project (But all function return 
a NULL pointer or 0).
I'm trying to call the caml_startup function but it freeze. So I look 
into Ocaml source to know on which function it relies.
Then in my main I call (instead of caml_startup) 
caml_init_ieee_floats(), caml_stat_alloc(), 
caml_register_custom_operations()...

I put debug information on all my functions to know which functions are 
called. Then the caml_stat_alloc work well but if I call the 
caml_register_custom_operations function it freeze...
So I copy the code of the caml_register_custom_operations function and 
renamed it caml_register_custom_operations1...I removed all code of this 
function (so the function do nothing)...

So if I call caml_stat_alloc() function it work...
If I call the caml_register_custom_operations1 it work also
But if I call the caml_stat_alloc() and the 
caml_register_custom_operations1 after... It freeze.... And I don't know 
why!!!

There is the code... If someone has an idea....

Regards
David LONY


/* Include definitions of the multiboot standard */
#include <multiboot.h>
#include <x86_videomem.h>
#include <caml/mlvalues.h>
#include <caml/callback.h>

struct custom_operations_list {
  struct custom_operations * ops;
  struct custom_operations_list * next;
};

extern struct custom_operations caml_int32_ops;

void caml_register_custom_operations1(struct custom_operations * ops)
{
sos_x86_videomem_putstring(1, 0, SOS_X86_VIDEO_FG_WHITE | 
SOS_X86_VIDEO_BG_BLACK,"caml_register_custom_operations1");
}

/* The C entry point of our operating system */
void sos_main(unsigned long magic, unsigned long addr)
{
  static char * argv[]={ "ocaml", NULL };
  int test;
  int result=11;

  multiboot_info_t *mbi;
  mbi = (multiboot_info_t *) addr;

  sos_x86_videomem_setup();
  sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLACK);
  if(result == 11)
  {
        sos_x86_videomem_putchar(1, 0, SOS_X86_VIDEO_FG_WHITE | 
SOS_X86_VIDEO_BG_BLACK,'A');
  }
  else
  {
        sos_x86_videomem_putchar(1, 0, SOS_X86_VIDEO_FG_WHITE | 
SOS_X86_VIDEO_BG_BLACK,'B');
  }

caml_init_ieee_floats();
test  = caml_stat_alloc(sizeof(int));
caml_register_custom_operations1(&caml_int32_ops);

  /* An operatig system never ends */
  for (;;)
    continue;
}



David LONY a écrit :
> Does anyone can explain to me how the function caml_startup works ? 
> Does it relies on malloc or free function or any functions of the C 
> library ?
> I've tried to look for an explanation on the Ocaml manual but I found 
> nothing...
>
> Regards.
> David LONY
>
> David LONY a écrit :
>> Hi all,
>>
>> I'm currently trying to make a multiboot sector with ocaml code. 
>> Unfortunately, it doesn't work bu I don't know why...
>> To do that, I made a small program in ocaml :
>>
>> let test_char a = a+1
>> let _ = Callback.register "caml_test_char" test_char;;
>>
>> I also made a dummy libc  (all functions return 0 or NULL pointer) 
>> because I have to provide all these functions if a wants to 
>> statically link a C objects..
>> This is my main file with the entry point of the kernel :
>>
>> /* Include definitions of the multiboot standard */
>> #include <multiboot.h>
>> #include <x86_videomem.h>
>> #include <caml/mlvalues.h>
>> #include <caml/callback.h>
>>
>> /* This is the entry point of the kernel */
>> void sos_main(unsigned long magic, unsigned long addr)
>> {
>>  static char * argv[]={ "ocaml", NULL };
>>
>>  multiboot_info_t *mbi;
>>
>>  /* Retrieve grub information (memory...etc) */
>>  mbi = (multiboot_info_t *) addr;
>>
>>  caml_startup(argv);
>>
>>  /* Clean the screen and put a 'A' on it */
>>  sos_x86_videomem_setup();
>>  sos_x86_videomem_cls(SOS_X86_VIDEO_BG_BLACK);
>>  sos_x86_videomem_putchar(1, 0, SOS_X86_VIDEO_FG_WHITE | 
>> SOS_X86_VIDEO_BG_BLACK,'A');
>>
>>  /* An operatig system never ends */
>>  for (;;)
>>    continue;
>>
>>  return;
>> }
>>
>>
>> But qemu freezes when I call the caml_startup function (If I removed 
>> it, it works well...)...Perhaps the caml_startup function relies on C 
>> function that I don't implements ?
>> If someone have an idea.... Because I must call this function 
>> (caml_startup) in order to call my ocaml function (test_char)...
>>
>>
>> Thanks a lot.
>> Regards,
>> David LONY
>>
>>
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>
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